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Size

property Size: Integer read write;

Example​

function DeclaredFieldSize(const Data: TvxClientDataSet; const Name: string): Integer;
begin
  Result := Data.FieldByName(Name).Size;
end;

Usage​

Gets or sets type-specific field schema size while the owning dataset is inactive; meaning varies by string, byte, BCD and fixed-size types.

  • Configure size before opening fields/datasets, preferably through governed module/query configuration.
  • Interpret units using DataType and the field class; do not assume bytes equal characters.
  • Do not change it merely to bypass an overlength value—fix the integration/schema contract.

Additional Technical Info​

Size is field-definition metadata whose units and valid range are defined by the concrete field class.

Source-backed behaviour​

The base getter returns FSize. The setter calls CheckInactive, calls virtual CheckTypeSize, then stores the value. Base TField.CheckTypeSize permits only zero for non-blob fields; descendants override it. String descendants accept non-negative character lengths, byte/varbyte and BCD descendants apply their own size/precision semantics, and fixed-size numeric/date fields conventionally use zero. Assigning while the dataset is active or opening raises.

The value is not DataSize, which reports native buffer bytes, and not DisplayWidth. Changing it does not resize an already-open database column or update an external schema. A value acceptable to the Delphi class can still disagree with provider/database metadata and fail when the dataset opens or persists data.

Official RTL references​

Created 2026-07-15